The present invention relates to a cylinder valve drive for internal combustion engines,
JP-A 63-117109 discloses a cylinder valve drive for an internal combustion engine, A valve train is operable in a first state to transfer the rotational motion of a pair of low lift cam lobes of a camshaft to the reciprocating reciprocal motion of a pair of valve lifters for cylinder valves against valve springs. The valve train is also operable in a second state to transfer the rotational motion of a high lift cam lode, situated between the pair of low lift cam lobes, to the reciprocating motion of the pair of valve lifters against the valve springs. Specifically, a third lifter is arranged between the pair of valve lifters to follow the shape of the high lift cam lobe, and the pair of valve lifters carry hydraulic pistons or plungers. The third lifter is formed with bores adapted to mate with the plugere. In the second state, the plungers project into the mating bores of the Third lifter so that the pair of valve lifters follow the shape of the high lift cam lobe. According to this known valve drive, the plungers are carried by the valve lifters and the third lifter is arranged adjacent the valve lifters. Thus, the valve train requires valve springs of increased strength to bear increased inertia owing to the plungers carried by the valve lifters. Besides, the valve lifters and third lifter are complicated in structure, difficult to machine and thus not suitable for manufacture.
An object of the present invention is to provide a valve drive of the above kind which adds little increase in inertia to the valve train.